Sorry, but after eight MS's since 2013, I think having the ESA is a no-brainer for nearly all owners, and ESPECIALLY so with the Model X, the Faberge Egg of automobiles.
The cost is nothing compared to one or two visits for major work, and too many of these cars require major work post-50k miles of use. MCU's die too easily and too often, and there are those door handles as well, at about $1k each . . . unless you learn to watch YouTube videos and get to have the fun of working on them yourself.
Also, you can't go to just any old shop for Tesla repairs--at least not yet. Thus, you're looking at full price repairs for anything out of warranty.
Lastly, as others have written, if I recall correctly, you can get a refund for the amount you've not used if you change your mind. (And selling a used Tesla without an ESA is very difficult/value losing.)
GET THE ESA! (It's for a good cause.)
A friend has a 2013 Model S. He did not get extended warranty and regrets it. He has spent around $10K in repairs. 4 Door Handles, Main Display, 12V Battery, Something with suspension and some other stuff (that was all after it went out of warranty). He's also on his 3rd drive unit (which was covered). He still loves the car and plans to buy another. But he said he will buy ESA next time.
Of my last 4 ICE cars since 2011, I've spent $0 on repairs (and not one under warranty repair). Only tires, oil etc. and other maintenance.